There are many conventional construction systems used for residential and light commercial building projects which employ sheathing over wood and/or light-gage steel frames combined with insulation and exterior cladding components that are faulty in allowing leakage, thermal bridging, air infiltration, decay, and attack by insects, mold and mildew as well as being vulnerable to fire.
For example, U.S. Pat. No. 6,510,667, Cottier et al. disclose a process for constructing a wall that includes the steps of erecting a rigid frame and attaching fiber reinforced cementitious sheets to the front and rear faces of the frame to form a void there between. This void is then filled with light weight aggregate concrete slurry and allowed to cure. The lightweight aggregate slurry to fill the void formed between the sheets may be of conventional composition and can incorporate pulverized scrap polystyrene foam material (“grist”) or expanded polystyrene beads. The cementitious sheets may comprise an autoclaved cured reaction product of metakaolin, Portland cement, crystalline siliceous material and water. U.S. Pat. No. 6,532,710, Terry discloses a solid monolithic concrete insulated wall system comprising 100% concrete construction on interior walls and exterior walls of buildings. Building materials consist of conventional concrete which is poured inside a cavity between two stay in place forming walls completely around the perimeter of the building. A highly cellular, lightweight material from quartzite, lime and water, known as Autoclaved Aerated Concrete (AAC) is used as a “stay in place” forming system of the exterior walls and interior walls. Two AAC walls run the entire perimeter of the respective building. The two walls are designed to form a cavity in which the concrete is poured. Anchor bolts, which are bolted deep into each side of the walls, hang into the cavity. For insulation purposes two sheets of foil backed insulation are attached to the inside of the outside wall by the anchor bolts. U.S. Pat. No. 7,204,060, Hunt discloses a system for manufacturing structures by the use of autoclaved aerated concrete. A first step is construction of the wall system, which comprises a first course of elongated AAC base blocks for placement on a pre-built foundation. U.S. Pat. No. 3,943,676, Ickes discloses a modular building wall unit comprising a hard foam layer and a concrete layer intimately bonded to each other along an interface between the layers. A reinforcing wire mesh matt is embedded in the hard foam layer and reaches with anchoring elements into the concrete layer which may also have embedded therein a further wire mesh matt. U.S. Published Patent Application No. 2008/0016803, Bathon et al. disclose a wood concrete composite system that comprises a wood construction component, an intermediate layer and a concrete construction unit. A single intermediate layer consists, for example, of a plastic foil, an impregnated paper, a bitumen pasteboard, a plastic insulating layer, a mineral insulating layer, an organic insulation material, a regenerating insulating material and up-poured and/or applied materials, which tie and/or harden at a later time, e.g. tar, adhesive, plastic mixtures. The range of types of concrete suitable for the concrete construction unit includes aerated concrete. U.S. Published Patent Application No. 2007/0062151, Smith discloses a composite building panel which includes a frame and a concrete slab made of aerated concrete. Fastened to the frame members is a reinforcing layer. The frame is oriented towards the interior side of the structure and the concrete slab is oriented towards the exterior side of the structure. The exposed frame provides cavities for the installation of plumbing, electrical wiring and insulation. U.S. Published Patent Application No. 2008/0010920, Andersen discloses a method of building construction wherein blocks and panels made from autoclaved aerated concrete are used as structural elements, including insulated panels having a rigid polyurethane/polyiscocyanurate foam core, are attached to structural elements via metal anchoring clips. U.S. Published Patent Application No. 2005/0284100, Ashuah et al. disclose a wall section having a sandwich like structure, which includes an external vertical panel and an internal vertical panel spaced apart in a parallel relationship, further including a vertical insulating layer. The external panel may be constructed of building blocks made of concrete or AAC. The internal panel may be constructed of wood panel. Between the panels there is a space, “core” which includes a vertical layer of concrete. The outer surface of the external panel is covered with a coating layer constructed of materials selected from among a group comprising of stone, marble, mortar, wood, aluminum, glass, porcelain and ceramics. U.S. Published Patent Application No. 2001/0045070, Hunt, Christopher M. discloses autoclaved aerated concrete panels, and method of making and using such panels, specifically for the construction of residential homes.
In addition to the conventional construction systems which employ sheathing over wood and/or light-gage steel frames combined with insulation and exterior cladding components, other conventional construction techniques use exterior walls composed of autoclaved aerated concrete (AAC) concrete.
Autoclaved Aerated Concrete (AAC) is a structural product composed of a mixture of cement, lime, water, and sand and aluminum powder. To manufacture AAC, cement is mixed with lime, silica sand, water, and aluminum powder and poured into a mold. The reaction between aluminum and cement causes microscopic hydrogen bubbles to form, expanding the cement to about five times its original volume. After evaporation of the hydrogen, the aerated concrete is cut to size and steam-cured in an autoclave.
It is an object of the present invention to overcome or substantially ameliorate at least some of the disadvantages of conventional construction techniques through the development of a building system that incorporates an exterior wall of autoclaved aerated concrete (AAC) attached to standard building framing through building clips and sealed with injected urethane foam insulation.
The building system of the present invention provides many benefits to the construction of residential and commercial buildings, including, but not limited to: providing high thermal resistance; preventing thermal bridging; providing increasing protection against water damage, vapor damage, fire, decay, mold or mildew damage, frost damage and insect damage; being impact resistance; reducing the need for painting or maintenance; the absence of any toxic compounds; providing a greater acoustical barrier and providing stronger shear strength. In addition, the building system is lightweight for transport and construction and compatible with existing plumbing, wiring, roofing, exterior stuccos and interior finishes commonly used.